The present invention relates to apparatus for tow a disabled vehicle, and in particular, to towing apparatus which can be mounted conveniently underneath a towing vehicle. With more particularity, the present invention relates to such an under-vehicle towing apparatus which allows the towing vehicle to be used for other purposes, even when a vehicle is being towed. For example, if the apparatus of the present invention is mounted to a conventional pick-up truck, the bed of the pick-up truck is left completely unobstructed for normal hauling purposes, even when a vehicle is being towed. The present invention also may find use in vehicles other than pick-up trucks, for example, underneath vans, utility vehicles and other trucks.
Various under vehicle towing apparatus are known. For example, U.S. Pat. Nos. 3,667,631 to Bishop, 4,557,496 to Sill, 4,473,237 to Lind and 2,715,470 to Marcus et al. show several types of under-vehicle towing apparatus. U.S. Pat. No. 3,667,631 to Bishop shows a hydraulic utility lift for trucks which is mounted beneath the bed of the towing vehicle. The apparatus there shown utilizes a complicated linkage for increasing the ground clearance of the utility lift. In this arrangement and also in the other known arrangements described in the above-mentioned patents, the apparatus disposed beneath the towing vehicle is disposed behind the rear axle of the vehicle. A disadvantage of this known arrangement is that the weight of the lifted towed vehicle is transferred mainly to the rear portion of the towing vehicle. Thus, weight distribution is poor, and a torque is created tending to lift the front end of the towing vehicle. With smaller trucks or trucks that have not been specifically strengthened or having an increased weight capacity, larger forces than can be handled by the rear suspensions of the towing vehicle may be encountered. Accordingly, in all of these known arrangements, if the towing vehicle is a smaller vehicle such as a pick-up truck, it is often necessary that the rear suspension of the vehicle be modified to handle the increased load.
U.S. PatS. No. 4,634,337 and 4,637,623 show other towing apparatus. However, these apparatus, although partially mounted below the vehicle body, are intended for specially modified towing vehicles. A further example of such a specially modified towing vehicle for wrecking work is that shown in a brochure of Holmes International, which is a division of Dover Corporation, and which apparently is also described in U.S. Pat. No. 4,634,337.
U.S. Pat Nos. 4,268,213, 2,603,370, 3,716,152, 2,951,601 and 2,283,443 show other examples of towing apparatus which are mounted in the body of the towing vehicle, for example, in the bed of a pick-up truck. In these known arrangements, the towing apparatus is mounted so that when not in use, it can be collapsed so that it will not interfere with normal usage of the truck bed, for example. However, in these known arrangements, when the towing apparatus is in use, the towing vehicle cannot be used for normal hauling purposes, as the upraised boom of the towing apparatus would interfere with such use.
Other patents which disclose various towing apparatus include U.S. Pat. Nos. 3,929,237, 3,700,125, 3,794,192, 4,000,823, 4,264,262 and 3,152,814 and 2,551,745. In all of these arrangements, the towing apparatus interferes with normal usage of the vehicle body, for example a pick-up truck bed, because the apparatus is mounted in the bed of the pick-up truck.